1. Field of Invention:
This invention relates generally to play balls, and more particularly to a variable-weight ball whose weight, which is mainly determined by a spherical layer of water pressed between an inner bladder and an outer casing, is adjustable to impart desired play characteristics to the ball.
2. The State of the Art:
The typical inflatable beach ball of the type in common use at outdoor swimming pools and beaches is made from 6 to 8 mil polyvinyl film material, the ball being provided with a valved air inlet so that it can be inflated by mouth.
Such thin-skinned beach balls are usually made in a diameter greater than that of a basketball or soccer ball, and they are relatively very light in relation to their surface area. As a consequence, the typical light-weight beach ball offers a much greater surface area to air than smaller balls, and little resistance to wind deflection, so that the ball cannot be thrown very far, and on a windy day it is almost impossible to play with a beach ball.
Because even a light wind deflects the beach ball, when the ball is thrown from one player to another, it is more likely to land in the water rather than in the hands of a player, and when blown into the water, the ball may be propelled to a distant point from which it cannot readily be recovered. Children often lose beach balls because of wind conditions.
But apart from the difficulty of playing with a light-weight play ball under windy conditions is that its lack of weight imposes other limitations on the ball. Thus so-called medicine balls are as large as beach balls, yet are useful for body building, weight hurdling and other conditioning exercises for which a light-weight beach ball is unsuited. On the other hand, a medicine ball, which is a heavy, stuffed leather-covered ball, is expensive; it cannot be collapsed and stored in a compact state; hence it is altogether unsuitable for casual beach use.
The above-identified copending application discloses a pneumatic play ball having an outer casing formed of non-stretchable material which when fully expanded assumes a ball configuration. Within the casing is an inflatable balloon whose stem initially projects through a small port in the casing. When the balloon is inflated, it expands to engage and conform to the inner surface of the casing, after which the stem is tied and pushed within the port whereby the balloon is then fully encased in the casing.
While a ball of the type disclosed in my copending application has distinct advantages over conventional beach balls, it is still lacking in weight and subject to wind deflection.
Inasmuch as the present invention is realized in a spherical ball having an inner bladder and an outer casing between which is a water-filled region, the U.S. Pat. No. 3,517,933 to Malkin is pertinent to the extent that it discloses a ball formed by inner and outer shells having liquid in the space between the shells. Also pertinent for the same reason is the U.S. Pat. No. 3,655,197 to Milbaum. But neither patent discloses a ball which is inflatable in the manner of the present invention and whose weight is variable.